Wuchereria bancrofti is a drcadful endoparasite of man; adults harbouring the lymphatic vessels and lymph nodes. Related Theory Its life history is digenetic, as it involves a primary hosi- humans and secondary hostthe blood-sucking female insects, Culex, Aedes or Anopheles. During heavy infection they block the lymphatic vessels and glands causing lymphatic obstruction so that lymph cannot get back to the circulatory system. Thus, accumulation of lymph in the affected organs swell fantastically leading to lymphoedema.